There is provided, between a master cylinder operated in accordance with driver's brake operation and a wheel cylinder corresponding to a wheel, a brake actuator configured to adjust a fluid pressure in the wheel cylinder to control braking torque to the wheel. Such an actuator includes a differential pressure valve as an electromagnetic linear valve configured to be driven to adjust a differential pressure between the master cylinder and the wheel cylinder, and a pump connected to a passage between the differential pressure valve and the wheel cylinder. When a value of driving current flowing to the differential pressure valve increases in a state where the pump discharges brake fluid, the differential pressure valve decreases in opening degree whereas the differential pressure, i.e. the fluid pressure in the wheel cylinder, increases. In contrast, when the driving current value decreases in the state where the pump discharges brake fluid, the differential pressure valve increases in opening degree whereas the differential pressure, i.e. the fluid pressure in the wheel cylinder, decreases.
As depicted in FIG. 16, the differential pressure valve has a hysteresis that a differential pressure actually generated between the master cylinder and the wheel cylinder (hereinafter, also referred to as an “actual differential pressure”) differs from each other between the case where the driving current value is increased and the case where the driving current value is decreased. Specifically, assume that an indicated current value is set to a predetermined current value A1 according to a required differential pressure PR when the actual differential pressure is increased to the required differential pressure PR. When the value of the driving current flowing to the differential pressure valve increases and reaches the predetermined current value A1 in this case, the actual differential pressure is increased to be approximate to the required differential pressure PR. However, when the actual differential pressure is decreased to the required differential pressure PR, the actual differential pressure is not decreased sufficiently and causes a difference between the actual differential pressure and the required differential pressure PR even if the driving current value decreases and reaches the predetermined current value A1. Note that the difference between the actual differential pressure of the case where a driving current value Id increases and reaches the predetermined current value A1 (the required differential pressure PR in this case) and the actual differential pressure of the case where the driving current value Id decreases and reaches the predetermined current value A1 will be also referred to as a “hysteresis amount HY”.
In this regard, a braking control device disclosed in Patent Literature 1 is configured to correct an indicated current value with a predetermined value according to the hysteresis and control a differential pressure valve in accordance with the indicated current value thus corrected when a differential pressure larger than a required differential pressure is decreased to the required differential pressure.